Map 1 shows broad geologic trends and patterns. The printed map and the dataset are not intended for detailed analysis or site-specific applications.

Map 1, Publication:Geologic Map of Pennsylvania (2nd ed.) is a 1:250,000-scale map of the bedrock geology of Pennsylvania compiled by T. M. Berg and others. Map 1 consists of three sheets: one showing geology in the western half of the state, one showing geology in the eastern half of the state, and one showing four northwest-southeast-trending geologic cross sections. The map is out of print, but PDF images of the map sheets are available.

Map 1, Data:Responding to numerous requests from government agencies and the private sector, the bureau used GIS technology to prepare a digital version of the bedrock geology of the state that was based on the 1980 published map and source materials used for that map. It was beyond the scope of the project to include new mapping done since the 1980 map was compiled; however, limited updates and changes were made where they could be easily incorporated.

Map 1 datasets consist of ArcView shapefiles: pagpoly (geologic units), padike (dikes), and pagarc (geologic contacts and faults). The datasets provide seamless bedrock geologic coverage for the state in a geographic coordinate system with an NAD 1927 datum. Included in the download are the datasets, metadata, referenced documentation, ArcMap styles, and style instructions. Free software that can be used to view the shapefiles can be obtained from the ESRI website: ArcGIS Explorer Desktop or AcGIS Explorer Online.

Questions or recommendations regarding the GIS dataset may be directed to Thomas G. Whitfield, P.G., 717–702–2017, Bureau of Topographic and Geologic Survey.

Historical Geologic Maps: Map 1 is the most recent, large-scale, statewide bedrock geologic map published by the Pennsylvania Geological Survey. Below are links that will take you to descriptions and images of much older geologic maps—maps that were published by the First and Second Geological Surveys of Pennsylvania.